The invention relates to improvements in papermaking machines, and more particularly to improvements in press sections and to an arrangement for reducing the vibration which occurs between two or more press rolls loaded to form a press nip for dewatering a traveling web of paper.
In papermaking machines, the web of paper is made continuously by depositing a slurry of fibers of wood or other vegetable substances with the addition of additives onto a traveling foraminous wire in order to form a layer which is dewatered through the wire and subsequently pressed and dried to form a continuous paper web or sheet. During this operation, the web formed on the wire is transferred, usually with one or two water absorbing felts between the succession of pairs of press rolls. A typical press roll will have opposed rolls pressure loaded against each other with one of granite and one of steel, although other materials may be used, which are pressed one against the other with considerable force to press water from the paper web and force it into the felt.
In the pressing operation the rolls necessarily operate at the high speeds of the machine and are subject to persistent vibration which leads to nonuniformity in the paper web and in the felt. Because the rolls are pressed together with substantial pressure, vibrations create minute variations in this pressure which translate into differences in water extraction, and the sheet produced, therefore, is not perfectly uniform and regular. Also, because of the high rotational speed of the rolls, load noise is produced, and in some instances the vibration will cause damage to the rolls and support members and other component parts.
It is accordingly an object of the present invention to provide a mechanism for satisfactorily reducing the vibration of press rolls in a papermaking machine which eliminates the disadvantages referred to and which inherently accompany vibration.
A further object of the invention is to provide an improved vibration absorbing or preventing mechanism of simplified construction for a paper press in a papermaking machine which has the operating life of the press and which does not require repair or attention during its operating life.
In accordance with the principles of the invention, the device contemplates the provision of a paper machine press with a pair of rolls forming a press nip with each of the rolls being supported by a pair of bearings fixed to the frame of the assembly for supporting the rolls. At least one of the rolls is provided with a vibration absorbing mechanism which includes a pair of layers of deformable elastic material disposed between the bearings and the frame. One of the layers is disposed so that it deforms by compression when the movement of the bearing is induced by vibration in a first direction, and the other layer is disposed in such position that it deforms by compression when the movement of the bearing takes place in the opposite direction.
Other advantages, features and objects will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings, in which: